First of all, congratulations on having your cholesterol checked! Having a screening test for abnormalities in your cholesterol levels is an important part of keeping up with your health, and most primary care doctors
will recommend that you do it with some regularity.
Cholesterol is checked with a simple blood test. You will feel a small poke from the needle and a small amount of blood will be withdrawn from the vein into a sample tube, which will then be sent to the lab and analyzed. Usually the results are available in a a day or two, and you usually will receive a call or a letter from your primary care doctor when the results are in.
A "cholesterol" test actually is broken down into various types of fat and cholesterol in your blood, including total cholesterol, triglycerides, high density lipoproteins (HDL), and low density lipoproteins (LDL). Your doctor will interpret all of these individual results and tell you what their significance is for your health.
In terms of preparation for the test, the main thing is that you cannot eat anything before having the test done. It is best to not have anything to eat after midnight and then have your blood drawn first thing in the morning.